Engine cooling system



APP-il 18, 1944. H. F. HAGEN E-r A1. n 2,347,153

ENGINE COOLING SYSTEM Filedsept. 25, 1942 Fon blades l' SPH?CounfersP/'n i APatented Apr. 18, 1944 v ENGINE COOLING SYSTEM Harold F.Hagen, Wellesley, and Robert T. Palmer, Sharon, Mass., assignors to B.F. Sturtevant Company, Boston, Mass.

Application September 25, 1942, Serial No. 459,608

3 Claims.

the engine. against the air into which the engine is moved by thepropeller, and by the suction iml pact of the flaps in the air exitopenings.

It can be demonstrated that a. properly designed mpropeller fan drivenby the airplane engine will provide the air pressure for cooling theengine when all of the cooling work is done by the fan, much moreefficiently than it can be provided by ram and ilap action, andfurthermore that such a fan will provide greater air pressures than canbe provided by ram and ilap action for effective cooling in very highaltitudes where due to the low density of the air, the ram and flapaction has been insunicientfor providing the necessary cooling.

However the cooling load varies and a fan designed for cooling an enginein stratosphere nyv ing would consume too much power at sea level. Forexample, it has been calculated that a fan for performing all of thework in -cooling a 2,200 horsepower motor at 40,000 feet, would itselfrequire 400 horsepower at sea level. It is desirable therefore to beable to reduce the fan power when reduced cooling will suilice and to dothis automatically, thus removing another burden from the pilot.

'I'his invention provides a propeller fan of the type disclosed in theH. F. Hagen application, Serial No. 357,767 led Sept; 21, 1940, forcooling an internal combustion engine; provides spin inducing vanes ofthe type disclosed in the H. F. Hagen Patent No. 1,989,413 which issuedJan. 29, 19.35, in the inlet of the fan, and provides a thermostaticcontrol responsive to the temperature of the engine for adjusting thespin vanes to increase the spin of the air entering the fan when thetemperature of the engine is below the critica1 temperature, and foradjusting the vanes to non-spin or counter-spin 'position when increasedcooling'is required. The spinning of the air entering the fan decreasesthe cooling eilect of the fan while reducing its load upon the engine.

This invention falso provides a manual control removing the load of thefan from the engine as when maximum climb, or maximum speed is requiredin combat. When this control is operated to remove the fan load from theengine, a signal in the pilots cockpit indicates continuously to himthat the cooling facilities are inactive and should be restored when theemergency is over.

Objects of the invention are to reduce the power required by a propellerfan driven by an engine for cooling the engine, by adjusting spininducing vanes in the inlet of the fan, under the control of athermostat responsive to en'gine temperatures, when maximum cooling isnot required, and to disconnect the thermostatic control and to adjustthe vanes to maximum spin position, when it is momentarily moreimportant to have maximum engine power available than itis to haveadequate cooling.

The invention will now be described` with reference to the drawing, ofwhich:

Fig. 1 is an elevation view, partially in section of one embodiment ofthis invention for cooling a radial, airplane engine;

, Fig. 2 is an enlarged plan view looking'downwardly upon a portion ofthe spin adjusting mechanism of Fig. 1;

Fig. 3 is a diagrammatic view illustrating the position of the spinvanes for counter-spin and for maximum spin, and

Fig. 4 is a diagrammaticview of the electrical control circuit used fordisconnecting the thermostat of Fig. l from control of the spin vanes.

The engine 6 is a conventional, radial, air cooled airplane engine andhas the usual propeller 1 with streamlined hub 8 mounted on the I theengine 6.

The spin vanes I6 are mounted between the propeller 1 and the fan I5.The bases of the vanes I6 are secured to the rods I1, -the lower ends ofwhich are pivoted in the outer housing of the bearing I8 for rotationthereon. The bearing I8 is supported by the shaft 9 and serves tosupport the inner ends oi the vanes I6.

The vanes I6 are attached at their tips to the rods I9 and are pivotedin the inner wall I2 of the cowl I0. The rods I9 have mounted thereonthe bevel gears ZIwhIch mesh with the bevel including the switch 28, thebattery 3i), the movable resistor contact 3i, the resistor 32, the-winding of the solenoid 25, and the contact 2S, placing the thermostat2l which adjusts the position oi the resistor contact 3i along theresistor 32.

The spring on the outer end of the plunger 25 opposes the action of thesolenoid, when the latter is energized,-in drawing in the plunger 26 andin consequently adjusting the vanes it towards open position.

In operation, as the engine temperature increases requring more cooling,the thermostat 2l adjusts the position of the contact 3l along theresistor 32 to decrease the volume of the resistor in the abovedescribed electric circuit, causing more circuit to iiow through thesolenoid 26 and the solenoid to draw in the plunger 25 for adjusting thevanes for less and less spin and ilnally for counter-spin. K

In an emergency such as combat with an enemy aircraft, when thepilotprefers increased engine power to adequate cooling, he moves the switch28 against the contact 3d. This opens the above described circuit anddeenergizes the solenoid 26. The spring 33 then moves the plunger 25 toadjust the varies i6 to maximum spin position, thus l,

gine power the switch 28 could be adjusted thereby to disconnect thethermostat andhvhen the throttle is again adjusted for cruising, theswitch could be adjusted to restore the cooling control.

The term closed position with reference to adjustment of the vanes i6,is intended to mean maximum spin position. 'I'he vanes may be blocked toprevent their complete closing so that some cooling is always provided.The term "open position is intended to mean the position ot no spin orthe position ofA counter-spin.

While one embodiment of the invention has been described for the purposeof illustration, it should be understood that the invention is4 notlimited to the exact apparatus and arrangement of apparatusillustrated-as modiiications thereof may be suggested by those skilledinthe art without departure from the essence of the invention.

.What is claimed is:

l. Cooling apparatus for an airplane engine comprising a propeller fanfor moving air over the heat exchange surfaces of the engine, spin vanesin the inlet of said fan, means including means responsive to changes inthe temperature of said surfaces for adjusting said vanes towards openposition upon temperature increases, means opposing the opening of saidvanes and exerting pressure to restore them towards closed position, asignal in the cockpit of the airplane,'and means manually operated fromthe cockpit of the airplane for rendering said temperature responsivemeans ineffective and for causing said opposing means to move said vanestowards closed position, and including means for energizing said signalfor indicating that said temperature responsive means has beendeenergized.

2. Cooling apparatus for an airplane engine comprising a propeller ianfor moving air over the heat exchange surfaces of the engine, spin vanesin the inlet of said fan, means including means responsive to changes inthe temperature of said surfaces for adjusting said vanes towards openposition upon temperature increases, means opposing the opening of saidvanes and exerting pressure to restore them towards closed position, andmeans for rendering said temperature responsive means ineiective and forcausing said opposing means to move saidvanes towards closed position.

3. Cooling apparatus for an airplane engine comprising a propeller `fanfor moving air over the heat exchange surfaces of the engine, means forvarying the volume of air moved by said fan, means including meansresponsive to changes in the temperature of said surfaces for adjustingsaid volume control means towards open positron upon temperatureincreases, means opposing the opening of said volume control means andexerting pressure to restore same towards closed position, and means forrendering said temperature responsive means ineective and for causingsaid opposing means to move said volume control means towards 'closedposition.

HAROLD F. HAGEN.l ROBERT T. PALMER.

